August 2017
Intermediate to advanced
360 pages
8h 35m
Chinese
Content preview from 算法技术手册（原书第2 版）
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空间树结构
｜
297
空间树结构
当信息过多而无法存放在主存中时，
R
树是为数不多的能够处理并提供优秀运行性能的
结构之一。传统的索引技巧都是针对一维数据，显然
R
树结构也适用于这些领域。
R
树上的操作包括插入和删除以及两类查询。你可以在
R
树中搜索指定的矩形区域，或
者找出与目标矩形有交集的矩形区域集合。
10.8.3 解决方案
例
10-8
中的
Python
实现为每个矩形关联了一个可选的标识符。该标识符可以用于从数
据库中取得实际的空间对象。
RNode
是
R
树的基本单元。每个
RNode
维护了一个边框区
域以及一个可选的标识符。如果
node.level
为
0
，则说明
RNode
是叶结点。每个
RNode
结点拥有
node.count
个子
结点，这些子结点存放在
node.children
列表中。当添加一
个
RNode
子
结点时，其父结点
node.region
必须通
过调整边框来包含新加入的子结点。
例
10-8
：
RNode
的
Python
实现
class RNode:
#
使用单调
递增计数器生成标识符。
counter = 0
def __init__(self, M, rectangle = None, ident = None, level = 0):
if rectangle:
self.region = rectangle.copy()
else:
self.region = None
if ident is None:
RNode.counter += ...
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I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.